05 Apr 05
Originally posted by SiskinI know someone who has promoted to a bishop to give him two bishops and was going to mate with those. Just to show off. Then he realised he had two lightsquared bishops and it was drawn. Serves him right.
There are chess problems which involve underpromotion to a bishop in order to solve. I doubt there are many actual real games where it is a necessity, but some people underpromote in a winning position just to show off
Whenever underpromotion comes up I give the Babson Task as an example:
White to move and Mate in 4.
The main solution lines are as follows:
1.a7!
1...axb1=Q 2.axb8=Q Qxb2(!) 3.Qxb3 Qc3 4.Qxc3#
Qe4(!) 3.Qxf4 Qxf4 4.Rxf4#
1...axb1=R(!) 2.axb8=R! Rxb2(!)3.Rxb3 Kxc4 4.Qa4#
2.axb8=Q? Rxb2! 3.Qxb3 1/2-1/2
1...axb1=B(!) 2.axb8=B! Be4(!) 3.Bxf4 B- 4.Be3(5)#
2.axb8=Q? Be4! 3.Qxf4 1/2-1/2
1...axb1=N(!) 2.axb8=N! Nxd2(!) 3.Qc1! Ne4 4.Nc6#
2.axb8=Q? Nxd2! 3.Qxf4+ Kc3
3.Rxf4+ Ne4
3.Qc1 Ne4
As you can see white must promote to the same piece that black does if he wants to mate in 4.
For more information and analysis http://www.xs4all.nl/~timkr/chess/babs.html
06 Apr 05
Generally underpromotion is used to prevent stalemate, sometimes to mate (with N), sometimes to confuse, and sometimes to remind the other bugger it's about time he resigned.
There's a nice article at http://www.xs4all.nl/~timkr/chess2/minor.htm where there's at least one underpromotion to B used in actual play.
06 Apr 05
1 edit
Originally posted by CrawlIceAs in all underpromotions the only sensible reasons are:
Okay, 99.5% of pawn promotions are to Q; most of the rest are to N, and a few are to R to avoid stalemates. Has anyone ever seen a game with an underpromotion to a B for legitimate chess reasons (and not just for the fun of it)?
Thanks, C.I.
1)To avoid stalemate (the most common)
2) To win a piece (Knight falls neatly here)
An example:
White cannot play:
1.cxbQ(R) due to stalemate; 1.cxbN leads to draw, so the only option is 1.cxbB and White wins.
06 Apr 05
Originally posted by ilywrinIsn't this an amazing study (the full one) where two different variants require two different underpromotions?
As in all underpromotions the only sensible reasons are:
1)To avoid stalemate (the most common)
2) To win a piece (Knight falls neatly here)
An example:
[fen]1r6/2P5/8/8/8/2N5/8/k6K [/fen]
White cannot play:
1.cxbQ(R) due to stalemate; 1.cxbN leads to draw, so the only option is 1.cxbB and White wins.
07 Apr 05
Originally posted by XanthosNZThis is pure beauty.
Whenever underpromotion comes up I give the Babson Task as an example:
[fen]Bq1B1K2/3Pp3/P3Pp2/P1p2P2/2Pk1b1R/1p6/pN1P1P2/QR6 w - - 0 1[/fen]
White to move and Mate in 4.
The main solution lines are as follows:
[b]1.a7!
1...axb1=Q 2.axb8=Q Qxb2(!) 3.Qxb3 Qc3 4.Qxc3#
Qe4(!) 3.Qxf4 Qxf4 4.Rxf4#
1.. ...[text shortened]... nts to mate in 4.
For more information and analysis http://www.xs4all.nl/~timkr/chess/babs.html